Deprecate and republish plugins with names starting with `css-`

[romainmenke]

see : #182 (comment)

These do not follow the naming guidelines and seemingly are not used much as direct dependencies.

Deprecating and republishing could go hand in hand with a more thorough cleanup and refactor.

[ehoogeveen-medweb]

Some inconsistencies I noticed regarding these:

• css-has-pseudo and css-prefers-color-scheme ship with all their files minified; css-blank-pseudo does not.
• css-prefers-color-scheme ships with browser.min.js but this file is identical to browser.js (as both are minified).

I don't really have an opinion about whether they should be minified or not (being able to read the code is nice if something goes wrong but these polyfills should be pretty much invisible anyway) but they should probably be consistent :)

[romainmenke]

Decided that we won't do this change in any time soon, so closing for now.